What is a parameter in statistical terms?

A parameter in statistical terms is a value that describes a population. It is a fixed number that summarizes or characterizes a distinctive aspect of an entire population, such as its mean, variance, or proportion. Parameters are typically derived from whole populations, which distinguishes them from statistics, which are values computed from samples. Understanding parameters is crucial because they represent the true characteristics of the population, while statistics allow researchers to make inferences about these parameters from sampled data.

For instance, if a researcher wants to find the average height of all adult males in a country, the actual average height calculated from the entire population would be the parameter. In contrast, if the researcher only measures a smaller group of adult males, the average height calculated from this sample would be a statistic, which serves as an estimate of the parameter.

The other choices, while related to concepts in statistics, do not capture the definition of a parameter. A numerical value describing a specific sample refers to a statistic, whereas a condition that remains unchanged is more accurately categorized as a constant or control variable, and a variable that can be tested refers to experimental conditions or independent variables rather than parameters.